<template>
	<div class="goods-sku">
		<dl v-for="item in goods.specs" :key="item.id">
			<dt>{{ item.name }}</dt>
			<dd>
				<template v-for="val in item.values" :key="val.name">
					<img :class="{ selected: val.selected, disabled: val.disabled }" @click="clickSpecs(item, val)"
						v-if="val.picture" :src="val.picture" />
					<span :class="{ selected: val.selected, disabled: val.disabled }" @click="clickSpecs(item, val)" v-else>{{
						val.name
					}}</span>
				</template>
			</dd>
		</dl>
	</div>
</template>
<script>
import { watchEffect } from 'vue'
import getPowerSet from './power-set'
const spliter = '★'
// 根据skus数据得到路径字典对象
const getPathMap = (skus) => {
	const pathMap = {}
	if (skus && skus.length > 0) {
		skus.forEach(sku => {
			// 1. 过滤出有库存有效的sku
			if (sku.inventory) {
				// 2. 得到sku属性值数组
				const specs = sku.specs.map(spec => spec.valueName)
				// 3. 得到sku属性值数组的子集
				const powerSet = getPowerSet(specs)
				// 4. 设置给路径字典对象
				powerSet.forEach(set => {
					const key = set.join(spliter)
					// 如果没有就先初始化一个空数组
					if (!pathMap[key]) {
						pathMap[key] = []
					}
					pathMap[key].push(sku.id)
				})
			}
		})
	}
	return pathMap
}

// 初始化禁用状态
function initDisabledStatus(specs, pathMap) {
	if (specs && specs.length > 0) {
		specs.forEach(spec => {
			spec.values.forEach(val => {
				// 设置禁用状态
				val.disabled = !pathMap[val.name]
			})
		})
	}
}

// 得到当前选中规格集合
const getSelectedArr = (specs) => {
	const selectedArr = []
	specs.forEach((spec, index) => {
		const selectedVal = spec.values.find(val => val.selected)
		if (selectedVal) {
			selectedArr[index] = selectedVal.name
		} else {
			selectedArr[index] = undefined
		}
	})
	return selectedArr
}

// 更新按钮的禁用状态
const updateDisabledStatus = (specs, pathMap) => {
	// 遍历每一种规格
	specs.forEach((item, i) => {
		// 拿到当前选择的项目
		const selectedArr = getSelectedArr(specs)
		// 遍历每一个按钮
		item.values.forEach(val => {
			if (!val.selected) {
				selectedArr[i] = val.name
				// 去掉undefined之后组合成key
				const key = selectedArr.filter(value => value).join(spliter)
				val.disabled = !pathMap[key]
			}
		})
	})
}


export default {
	name: 'XtxGoodSku',
	props: {
		// specs:所有的规格信息  skus:所有的sku组合
		goods: {
			type: Object,
			default: () => ({ specs: [], skus: [] })
		}
	},
	emits: ['change'],
	setup(props, { emit }) {
		let pathMap = {}
		watchEffect(() => {
			// 得到所有字典集合
			pathMap = getPathMap(props.goods.skus)
			// 组件初始化的时候更新禁用状态
			initDisabledStatus(props.goods.specs, pathMap)
		})

		const clickSpecs = (item, val) => {
			if (val.disabled) return false
			// 选中与取消选中逻辑
			if (val.selected) {
				val.selected = false
			} else {
				item.values.forEach(bv => { bv.selected = false })
				val.selected = true
			}
			// 点击之后再次更新选中状态
			updateDisabledStatus(props.goods.specs, pathMap)
			// 把选择的sku信息传出去给父组件
			// 触发change事件将sku数据传递出去
			const selectedArr = getSelectedArr(props.goods.specs).filter(value => value)
			// 如果选中得规格数量和传入得规格总数相等则传出完整信息(都选择了)
			// 否则传出空对象
			if (selectedArr.length === props.goods.specs.length) {
				// 从路径字典中得到skuId
				const skuId = pathMap[selectedArr.join(spliter)][0]
				const sku = props.goods.skus.find(sku => sku.id === skuId)
				// 传递数据给父组件
				emit('change', {
					skuId: sku.id,
					price: sku.price,
					oldPrice: sku.oldPrice,
					inventory: sku.inventory,
					specsText: sku.specs.reduce((p, n) => `${p} ${n.name}：${n.valueName}`, '').trim()
				})
			} else {
				emit('change', {})
			}
		}
		return { clickSpecs }
	}
}
</script>

<style scoped lang="scss">
@mixin sku-state-mixin {
	border: 1px solid #e4e4e4;
	margin-right: 10px;
	cursor: pointer;

	&.selected {
		border-color: $xtxColor;
	}

	&.disabled {
		opacity: 0.6;
		border-style: dashed;
		cursor: not-allowed;
	}
}

.goods-sku {
	padding-left: 10px;
	padding-top: 20px;

	dl {
		display: flex;
		padding-bottom: 20px;
		align-items: center;

		dt {
			width: 50px;
			color: #999;
		}

		dd {
			flex: 1;
			color: #666;

			>img {
				width: 50px;
				height: 50px;
				margin-bottom: 4px;
				@include sku-state-mixin;
			}

			>span {
				display: inline-block;
				height: 30px;
				line-height: 28px;
				padding: 0 20px;
				margin-bottom: 4px;
				@include sku-state-mixin;
			}
		}
	}
}
</style>